Improvement in machines for shearing boiler-plates



A. THOMSON. MACHINES Fon ,SHEARAING Boum-PLATES.

No.'19 3v,624,.f Patented July s1, 1877.

mmm-ll N.PETERS, FHOTO-LITHOGRAFHER, WASHINGTON p C.

UNITED STaTEs ENT OFFICE.

ALEXANDER THOMSON, OF FITCHBURG, MASSACHUSETTS.

Specication forming part of Letters Patent No. 193,625, dated July 31,1877 application filed May 23, 1877.

To all whom -it may concern.'

Be it known that I, ALEXANDER THOMSON, of Fitchburg, in the county ofWorcester and State of Massachusetts, have invented a new and usefulImprovement in Boiler-PiateShears, of which the following is aspecification The object of my invention is to cut a beveledge suitablefor calking on iron plates after they are bent or flanged in the sha-perequired in the construction ot'steam-boil ers, tank-work,

Svc.; and my invention consists of a spira-llyshaped shear-bladeattached to the arc-shaped end of its operating-lever, in combinationwith astationary convexlower blade and gage mechanism, as hereinafterdescribed and claimed.

In the drawings accompanying this specilication, Figure l is a sideelevation ot' my improved machine; Fig. 2, a plan view; Fig. 3, a frontview, and Fig. 4 a front view showing a modied form of the lo'wershear-blade.

A represents the body or bed-frame of the machine; B, the balance-Wheel,O, the driving-pulley; D, the gear; D', a pinlou on the drivin gshaft Afor communicating motion to the gear D, Iand E thc cam (shown by dottedlines) for operating the lever F, to which the spirally-shapedshear-blade J is attached. G is a gage-bar; H, the screw which works inthe nut K, and operates the gage-bar; I, the

sheared, and also when the movable bladel operates from within theboiler-head.

The lower blade M is formed with a convex or circular top, and isadapted to tit the under sideof a curved plate.

Having thus described my invention, I claim as new and desire tosecureby Letters Patent- The spiral shear-blade I, attached to thearc-shaped end ofthe pivoted lever F, in combination with the adjustablegage-bar G and adjustable convex stationary shear-blade M, substantiallyas herein described and set forth.

ALEXANDER THOMSON. Witnesses:

L. I. UNEAL, A. K. BROWNE.

